GREY AND DOLITTLE’S SIX KINGDOM CLASSIFICATION

GREY AND DOLITTLE’S SIX KINGDOM CLASSIFICATION

·  Though Whittaker’s Five Kingdom System solved many problems, lack of distinction between Archaebacteria (archaea) and Bacteria remained untouched.

·      Six kingdom classification was suggested by Gray and Doolittle (1982) and Carl Woose (1990) divided these six kingdoms into three domains on the basis of Gene sequence.

·     Grey and Doolittle (1982) proposed to classify organisms into two Superkingdoms the (i) Prokaryota and the (ii) Eukaryota.

·       The Superkingdom Prokaryota further divided into 2 Kingdoms (i) Archaeobacteria and (ii) Eubacteria, whereas the Superkingdom Eukaryota divided into 4 kingdoms, (i) Protista, (ii) Fungi, (iii) Plantae and (iv) Animalia. Therefore, they suggest adopting Six distinct kingdoms to classify all the organisms.